Internal grinding apparatus



July 12, w49,

J. M. LESUEUR INTERNAL` GRINDING APPARATUS 2 Sheets-Sheet l Filed March 24, 1945 Q NN my l2? i949 J. M. LESUEUR INTERNAL GRINDING APPARATUS 2 sheets-sheet 2 Filed March 24, 1945 Patented July 12, 1949 INTERNAL GRIN DIN G APPARATUS `llules Marcel Lesueur, Sevres, France Application March 24, 1945, Serial No. 584,512 In France April 4, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires April 4, 1961 4 Claims.

It is known that the internal grinding of previously bored holes is generally eli'ected by means of grinding spindles having a high speed of rotation, the most recent of which are mounted on ball bearings.

The latter although greatly appreciated heretofore, nevertheless have a serious inconvenience inherent to their very constitution.

In these spindles, in fact, the grinding wheel arbor is appreclably overhang, at least to the distance corresponding to the depth of the hole to be internally ground, and, in addition, it must have a^diameter smaller than the diameter of said hole; if therefore, holes of small diameter and great depth are to be internally ground, the grinding wheel proper,` to which very high speeds must be imparted owing to the small diameter thereof, assumes, in its turn, a gyratory movement which prevents any eilcient work and which can even determine the breaking of the grinding wheel arbor. On the other hand, the ball bearings cannot withstand these Very high speeds which can reach more than 100,000 revolutions per minute.

The internal grinding apparatus forming the subject-matter of the present invention is devised in order to remedy these drawbacks, as it allows of causing the grinding spindle to rotate, whatever may be the diameter of the grinding wheel,

at the normal grinding speed, as is already done for eiecting external grinding.

An embodiment of the subject-matter of the invention is illustrated by way of example, in the accompanying drawings, in which:

Fig. 1 is a longitudinal section, illustrated on an enlarged scale, of the grinding spindle and of a part of the frame on which it is mounted.

Fig. 2 shows, in longitudinal section, on a smaller scale, the internal grinding apparatus comprising said spindle.

Fig. 3 is a vertical section along line III--III of Fig. 1, but further enlarged for greater clearness.

Fig. 4 is a general diagrammatic View of the apparatus in operative position.

Fig. 5 is a longitudinal section, on a greatly enlarged scale, showing a part of the spindle near the grinding wheel end.

In order that the invention may be more clearly understood, it can already -be stated that in fact the grinding wheel shown in the drawings has been devised for internally grinding a hole ve millimeters in diameter, it being moreover understood that the apparatus allows of internally l 2 grinding holes less than three millimeters in diameter although of great depth.

As will be seen rst of all in Fig. 1, the apparatus according to the invention is composed of a frame I, of any suitable shape and dimensions, in which a frusto-conical portion of the head stock 2 is secured at one side by a nut 3 and locknut 4, and at the opposite side by a nut 5 which allows unlocking of the head stock when it is to be removed from the frame. At the front, that is to say, towards the grinding wheel, the head stock is externally cylindrical according .to a diameter in harmony with the diameter of the hole to be internally ground; said head stock is tubular r throughout, and its bore is cylindrical for a part of its length, but frusto-conical towards its front end, the small diameter of the cone being at the front end, towards the grinding wheel.

A bushing 6, externally provided with longitudinal utes 61 (see Figs. 3 and 5) is housed in the conical bore of the front end of the head stock 2, in which it is held clamped by means of the tube 'I actuated by the hollow screw 8 which is screwed in the interior of the head stock; internally, bushing 6 is also conical, but said conicity is in reverse direction to that of the outer conicity, the large diameter of the inner cone being consequently at the front.

A grinding wheel 9 is mounted at the end of the grinding spindle I0 on which is provided, immediately behind the grinding wheel, this eliminating all overhanging conditions, a conical bearing fitted in the inner cone of bushing 6; the other end of the spindle is secured by a conical coupling in sleeve II, and the two members are rendered rigid by means of the nut I2 and lock nut I3.

An annular chamber is provided between the inner wall of tube 'I and the grinding spindle I0 for lubrication. The oil under pressure admitted through duct I4 lls said chamber and lubricates the conical bearing of spindle I0 in bushing 6; for that purpose, the driving sleeve I l terminating within the head stock 2 is externally provided with a screw thread of suitable pitch which forces the oil towards the front of the apparatus.

On the other hand, the outer wall of tube 'I and the bore of the head stock 2 also form an annular space in which water under pressure is admitted through the duct I5; said water first of all produces the cooling of bushing 6 by passing in the external longitudinal flutes from where it is moreover driven in order to spray the grinding wheel 9 and the wall in course of grinding and drive out the dust. The water can obviously be replaced by any other suitable, liquid or gaseous fluid, either by a mixture of air and atomised water, or by compressed air.

The control for the grinding spindle is more especially illustrated in the general view of Fig. 2.

Sleeve ll which is connected to spindle l as above stated is fitted and clamped in an arbor $3 by which it is driven; two nuts l'l-I'I lock these two members one on the other, whilst allowing the adjustment of the longitudinal position of sleeve Il and consequently of spindle I0, which allows of taking up the play, at every instant, of the spindle in its bushing 6.

The arbor I6 is shaped so as to constitute a control pulley at its median part, and to form at each side of said pulley, a biconical bearing, having unequal cones which rotate in two also biconical bushings Iii-i8, the long cone portion serving as bearing proper and the more open portion of the cone serving as abutment. Said bushings can slide with slight friction in two sockets Iii-I9 tightly fitted in frame I; the two nuts 2li-2i) allow the longitudinal adjustment of said bushings and consequently the taking up of the play of the pulley carrying arbor I6.

Said arbor is actuated by means of a control pulley mounted on the frame, in the axis A-A and not shown. A roller winding up a belt 2l rotates about the spindle 22 rigidly secured in two circular cheeks 23-23 which freely rotate on two bearings of sockets I9.

The numerous advantages obtained with the above described arrangements will be easily understood:

Whatever may be its diameter, the grinding spindle is supported at the end of the head stoel: and at the very level of the grinding wheel, which, as already speciiied, eliminates any overhanging conditions and allows the internal grinding of holes of very small diameter and great depth; said bearing being conical, the taking up of the play of the spindle is facilitated.

The pulley-carrying arbor is independent oi the grinding spindle, and as its two biconical bearings are also independent of the bearing of the spindle which is located at the other end of the apparatus, the play of said pulley-carrying arbor, which can moreover also be easily taken up, has in any case, only an insignificant action on the rotation of the grinding wheel.

The bushing supporting the grinding spindle is suitably internally lubricated and suitably cooled externally by a uid, water or the like, which then ensures the cleansing of the grinding wheel and of the hole to be internally ground.

And, finally, all this allows of obtaining high normal speeds for the cutting action of the grinding wheel and, consequently, of using very soft grinding wheels operating under a low pressure. Very slight wear of the bearings results therefrom as well as perfect internal grinding.

It is to be understood that constructional or detail modifications can be made in the device above mentioned without the features of the invention being changed thereby.

What I claim as my invention and desire to secure by Letters Patent is:

1. An internal grinding machine, especially 'for bores of small diameter, having a grinding spindie, a driving sleeve for said spindle, a head stoel; supporting the spindle and the driving sleeve, a grinding wheel rigidly secured on the spindle in immediate proximity to the head stock, a bushing interposed between the spindle and the head stock, in contact with the spindle by means of a conical bore the largest diameter of which is located towards the grinding wheel, the bushing being in contact with the head stock by means of a conical bearing the conicity of which is in reverse direction to said bore, and longitudinal flutes on said conical bearing.

2. An internal grinding machine, especially for bores of small diameter, having a grinding spindie, a driving sleeve for said. spindle, a head stock supporting the spindle and the driving sleeve, a grinding wheel rigidly secured on the spindle in immediate proximity to the head stock, a bushing interposed between the spindle and the head stock, in contact with the spindle by means of a conical bore the largest diameter of which is located towards the grinding wheel, the bushing being in contact with the head stock by means ci a conical bearing the conicity of which is in reverse direction to said bore, longitudinal flutes on said conical bearing, a bracing tube mounted in the head stock. about the spindle and engaging the conical bushing, a hollow screw engaging the head stool: and bearing against the bracing tube for taking up the play between said conical bushing and the head stock, a lubricant chamber between the bracing tube and the spindle, a cooling water chamber between the bracing tube and the head stock, and a screw thread for the circulation of oil on the outer wall of the sleeve driving the spindle, at the end of said sleeve which is contiguous to the spindle.

3. An internal grinding machine, especially for bores of small diameter, having a grinding spindle,

. a driving sleeve for said spindle, a head stock supporting the spindle and the driving sleeve, a grinding wheel rigidly secured on the spindle in immediate proximity to the head stock, a bushing interposed between the spindle and the head stock, in contact with the spindle by means of a conical bore the largest diameter of which is located towards the grinding wheel, the bushing being in contact with the head stock by means of a conical bearing the conicity of which is in reverse direction to the bore, longitudinal flutes on said conical bearing, a bracing tube mounted in the head stock, about the spindle and engaging the conical bushing, a hollow screw engaging the head stock and bearing against the bracing tube for taking up the play between said conical bushing and the head stock, a lubricant chamber between the bracing tube and the spindle, a cooling water chamber between the bracing tube and the head stock, a screw thread for the circulation of oil on the outer wall of the sleeve driving the spindle, at the end of said sleeve which is contiguous to the spindle, a frame supporting the head stock, ducts in said frame respectively for the circulation of water and the circulation of oil, and corresponding ducts formed in the head stock, respectively communicating with the cooling water chamber and with the screw thread for the circulation of oil.

4. An internal grinding machine, especially for bores of small diameter, having a grinding spindle,

a driving sleeve for said spindle, a head stock supporting the spindle and the driving sleeve, a grinding wheel rigidly secured on the spindle in immediate proximity to the head stock, a bushing interposed between the spindle and the head stock, in contact with the spindle by means of a conical bore the largest diameter of which is located towards the grinding wheel, the bushing being in contact with the head stock by means of a conical bearing the conicity of which is in reverse direction to the bore, longitudinal flutes on said conical bearing, a bracing tube mounted in the head stock, about the spindle and engaging the conical bushing, a hollow screw engaging the head stock and bearing against the bracing tube for taking up the play between said conical bushing and the head stock, a lubricant chamber between the bracing tube and the spindle, a cooling water chamber between the bracing tube and the head stock, a screw thread for the circulation of oil on the outer wall of the sleeve driving the spindle, at the end of said sleeve which is contiguous to the spindle, a frame supporting the head stock, ducts in said frame respectively for the circulation of water and the circulation of oil, corresponding vducts formed in the head stock, respectively communicating with the cooling water chamber and the screw thread for the circulation of oil, a hollow shaft coaxial and rigid with the sleeve driving the spindle, two bearings supporting said hollow shaft in alignment with 6 the frame supporting the head stock, a driving pulley formed on said hollow shaft between its bearings, and means for adjusting the longitudinal play between the spindle and the conical bushing.

JULES MARCEL LESUEUR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,078,560 Shearer Nov. 11, 1913 1,181,992 Churchill et al May 9, 1916 2,201,955 Indge May 21, 1940 FOREIGN PATENTS Number Country Date 401,540 Great Britain Nov. 16, 1933 

